In order to improve the accuracy of channel estimation in mobile communication, a conventional technique is proposed for carrying out tentative decision of data symbols, calculating a channel estimation value, weighting the channel estimation value according to the reliability of tentative decision data and combining two channel estimation values of the weighted channel estimation value and a channel estimation value calculated from the pilot symbol (refer to Patent Document 1).
Upon channel estimation, this conventional technique uses a channel estimation value alone calculated from tentative decision data with the high reliability, and so improvement of the accuracy of channel estimation is anticipated.    Patent Document 1: Japanese Patent Application Laid-Open No. 2000-82978